Track 06 from Celestial Wizardry ~ Magical Astronomy, a Touhou music CD.
It starts out very structured and calm, and then ends in a very messy piano part. Like the name implies, it could fit a café or space level, but also anywhere with an exploration-y vibe. The song would best suit longer levels due to its length.
Special thanks to musicalman for helping me adjust the echo and panning, this port would not sound as good without him.